Ingot mold



July v21, 1942. E. GATHMANN INGOT MOLD 1 2 W m 0 omw may w L Y F v a 5 4 m 4 m F2 N L W X. a B r July 21, 1942.

E. GATH MANN 2,290,804

meow MOLD 7 Filed July 9, 1941 2 Sheets-Sheet 2 Fig.4.

mi/ I Qafhmann .NI Q I.

the improvement of ingot molds.

Patented July 21, 1942- UNITED STATES PATENT OFFICE mao'r MOLD Emil Gathinann, Baltimore, Md, assignor to Gathmann Research Incorporated, Catonsville, Baltimore, Md., 2. corporation'ol' Maryland Application July 9, 1941, Serial No. 401,663

3 Claims. (Cl. 22-139) This invention relates to ingot molds, and more particularly to improvements in cross sectional contours of ingot mold chambers. According to one of its" aspects, the present invention I provides improvements in the inventions disclosed and claimed in my United States Patent 2,240,396, issued April 29, 1941, and the earlier United States patents referred to therein.

My aforesaid United States Patent 2,240,396 discloses an ingot having across sectional contour including two primary side portions each having longitudinally extending, outwardly projecting, marginal portions, a longitudinally extending, abruptly curved, convex, central portion, two relatively smoothly curved concave porattributable at least in part to the provision of the abruptly curved, convex, central portion or rib flanked by the relatively abruptly curved, concave portions.

Molds having complementary chamber c'ontours (also as disclosed and claimed in my prior Patent 2,240,396) for producingisuch ingots have had a commercially acceptable life of about seventy heats, i. e., a capacity to remain in usable condition throughout the pouring of up to seventy ingots in a single mold. Ordinarily the ,molds have become unusable after about seventy heats due to the formation of fire cracks adjacent the centrally disposed, abruptly curved, concave mold wall portion.

One'of the objects of the present invention is so' to adjust or modify the relative lengths of the radii of the abruptly curved concave central mold wall portion (convex ingot portion) and the relatively abruptly curved convex mold wall portions (concave ingot portions), which flank it,

as to reduce fire cracking of the mold and hence provide for an increased mold life. Primarily,

therefore, the present invention has to do with Nevertheless, my improved mold contour embodying the present invention makes possible the commercial production of. improved ingots. This is due to the fact that mold fire'cracks may develop gradual-- ly, beginning long prior to the molds becoming cracked or otherwise worn out to the point where it must be discarded. In commercial practice it is common to use molds even after fire cracks have started to form, providing the cracks are not so large as to make it certain that good ingots cannot beproduced safely. Many ingots cast in molds having small fire cracks turn out to be free from serious defects, but sometimes even small fire cracks in a mold may cause the ingot itself to crack. It seems possible that the sharp edges along the mold cracks may start cracks in the ingot (casting) in much the same way-that unfilleted comers or edges in a sand mold may start cracks in a casting formed therein. It thus is apparent that' by reducing the formation of mold fire cracks it is possible also to improve the quality-of ingots cast therein, and accordingly another object of the present invention is to provide for the commercial productionv of sounder and improved ingots.

Further objects will become apparent from a reading of the following ,detailed' description, the appended claims, and the accompanying drawings, in which:

Figure 1 is a central vertical sectional view of an ingot mold embodying the invention;

Figure 2 is a horizontal half section taken on the line 22 of Figure 1 and drawn on an enlarged scale;

Figure 3 is a somewhat diagrammatic partial 1 horizontal section taken on the line 2-2 of Figure 1 and drawn on a further enlarged scale;

Figure 4 is a perspective view of an ingot embodying the invention and having the contour complementary to the mold contour disclosed in-Figures 1, 2, and 3;

Figure 5 is a horizontal sectional view of the ingot shown in Figure 5 and drawn on an enlarged scale; and E Figure 6 is a diagrammatic partial horiaontal section on the line. 55 of Figure 4 and drawn on a more enlarged scale.

The invention may be embodied in various classes of molds. Generallystated, most commercial ingotsare .cast in vertically extending molds which taper outwardly from bottom to top (big-end-up molds) or taper outwardly from top to bottom (big-end-down molds). The largest tonnage of high grade or quality steel is .produced in big-end-up molds, and the invention is illustrated as being embodied in a big-end-up mold and ingot. However, it will be apparent from the following description that the invention may also be embodied in molds and ingots differing as to those characteristics or contour which are not pointed out herein as being essential features of the present invention.

Figures 1, 2, and 3 show, by way of illustration, a mold M having having a big-end-up matrixor chamber tapering outwardly from bot-.

tom to top and being generally dodecagonal in heat absorbing material, such as cast iron, and

of the mold when setting up a jag of molds and when removingingots from the molds? The v inwardly tapering walls of' the mold chamber merge at their bottoms with'a concavo-convex necked-in bottom portion B which may have a contour in vertical section somewhat similar to that disclosed in my Patent 2,047,098, of July 7,.

1936. The mold bottom wall isformecl with the usual bottom opening which receives a sealing or stripping plug P.

the mold primary side .wall portion constituted as set forth above will be subjected to the initial rolling pressure.

The relatively smoothly curved convex mold wall portions 44 are struck from the common center C on or substantially on the transverse center line T T and bothwall portions 44 form segments of the periphery of the same circle.

Thus, as indicated by the dotted arcuate line IV As is well known, ingots which are cast on end or in vertical position may be similar or symmetrical as to all their sides, or theymay be'i'n the form of slabs in which the two wider sides correspond with each other in outline and the narrower sides are different from the wider sides but correspond with each other. The mold shown in'Figures l to 3, inclusive, has 'aningot forming chamber or matrix of generally dodecagonal cross section two center lines of which are indicated at T -T and I -T The mold is defined by twelve primary side walls arranged in pairs, theside walls of each pair being disposed opposite each other, the arrangement being such that only the ingot sides formed by=one pair of oppositely disposed primary mold walls will contact the rolls during the initial roll pass.

, All twelve side walls of the mold chamber are in Figure 3, each smoothly curved convex wall portion 4 is a continuation of the other wall portion 4. The radius R of each relatively smoothly curved convex wall portion 4 is substantially longer than the radius R. of the relatively abruptly curved concave wall portion 2, and also is substantially longer than the radii R of the relatively abruptly curved convex wall portions 3.

' The ratio of the radius R to the radius R should of the same contour, so that a detailed a I 1 tion of one side wall will be sufiicient. Eac of the side walls is formed of a plurality of sec;

tions or portions having relative dispositions,

in tests and in commercial production to eliminate, more completely than tha's been possible heretofore, fire cracks and ingot cracks of the Referring to Figure 3; the single primary side f kind referred to. 4

wall shown comprises an outwardly projecting,

arc struck on a radius R. from a center C, which "center lies on or substantially on the transverse center line T T normal to the side wall considered as a whole. The opposite edges of the concave wall portion 2 merge with abruptly convex wall portions 3-4 defined by arcs whose radii R -R respectively have their centers C -C lying outwardly beyond the side wall and being disposed relatively on opposite sides of the transverse-center line T T The relatively abruptly curved convex wall portions 3-3 mergerespectively .with relatively smoothly curved convex, wall portions 44 defined by arcs whose radii R -R have substantially a common center C lying substantially: on the transverse center line T T Thewall pore tions 44 merge respectively with outwardly projecting primary side wall marginal ,portions 5-5.. .In the mold shown in Figures 1, 2, and

and in eifect are parts of the adjacent primary sides. An ingot cast in the mold will have -a '55 curvatures; and extents which have been 1 not be less than four to" one, and it should .be greater than four to one inmost cases, particularly-in the larger mold sizes. The mold shown in Figures 1 to 3, inclusive, has a maximum width of approximately twenty inches, and the radius R is about eleven times as long as the radius R As explained in my prior Patent 2,240,396, this construction provides a relatively deep salient on the neutral line of shrinkage of the ingot cast in the mold, and provides a very gradual slope to the marginal portions of the primary side surface of the ingot. The abrupt change of direction provided by the acutely curved convex portions 3-3 and concave portion-2 provides a correspondingly abrupt outwardly extending salient on the ingot lying on the neutral line of shrinke t In accordance with the present invention, a .jmold chamber contour as previously described has'the distinguishing feature that-the radii R .of -the arcs defining the relatively abruptly curved, convex mold wall portions 3, although much shorter than the radii Rfare materially longer than the radii R of the arcs defining the con-' abruptly concave, wall portion 2 defined by an cave central portions 2. Preferably, and as shown in Figures 2 and 3, the radii R are about twice as long as the radii R Testing and observation of many tons of molds used in commercial ingot production have established that this characterizin'g feature very substantially reduces the formation of .fire cracks in the molds; and, as a consequence, minimizes the formation of ingot cracks heretofore induced by mold cracks.

Preferably, the root or'bottom of the depression formed by the concave moldwallpart 2 is disposed alittle inwardly'of the outermost portions of the marginal walls 5-5. An ingot cast ina-mold so formed and having a corresponding or complementary contour will not cause difllculty sometimes encountered when as many 'as'three' more than is intended results in rocking or cant ing of the ingot in the rolls and consequent diamond-shaping" in reduction. The arrangement of the concave wall portion 2 inwardly of the marginal wall portions 5 as described above obviates such difficulties in rolling, as is described in more detail in my Patent 1,810,041, of June 16, 1931. I 9

An ingot produced in a mold such as disclosed in Figures 1, 2, and 3 will have a contour side surface contoursuch that the metal at and under the primary side surface corresponding to generally complementary to or corresponding with the mold wall contour described abqve.

Such an ingot I is shown in Figures 4, b, and'6, and the various ingot surface portions are designated by the same numerals as those which designate corresponding wall portions of tlie mold with the exception that the numerals designateach of the primary ingot sides includes an outwardly projecting, relatively abruptly curved, convex, central portion 2', the opposite longitudinal edges of which merge with relatively abruptsmoothly curved convex wall portions, at any cross section of the mold, being defined by arcs having substantially a common center lying substantially on said transverse center line, and said i relatively abruptly curved convex wall portions ing the ingot surface portions are primed. Thus, at any cross section being defined by arcshaving 1y curved concave portions 3'--3', which in turn merge with relatively smoothly curved concave portions 4'-4' which are flanked by outwardly projecting convex marginal portions 5-5. The common center of the smoothly curved convex portions 4'4' is located on or substantially on the neutral line of peripheral shrinkage N ---N normal to the side surface as a whole. The radii of the arcsdefining the convex portions 4-4' are substantially longer than the radii of the arcs defining the abruptly curved, concave portions 3-3, which latter radii have their centers on opposite sides of the neutral line of shrinkage N N and also are substantially longer than the radius of the abruptly curved, convex, central portion 2', which has its center on the neutral line of'peripheral shrinkage -N --N within the ingot. The radii of the arcs defining the abruptly curved concave ingot portions 3' are materially longer than and preferably not less than about twice as long as the radii of the arcs defining the convex central ingot portion 2'.

These various radii are not indicated in Figures 4, 5, and 6, but they have the same relation to each other as the radii of the corresponding wall portions of the mold as shown in detail in Figure 3. The other neutral line of shrinkage is indicated at N -N 'It will be observed that the relatively smoothly curved concave side surface.

portions 4--4' of the ingot form segments of the same circle as is indicated by the dotted connecting line IV in Figure 6.

The mold disclosed herein has a contour embodying the invention and has been successful in the elimination of a very large part of the difficulty previously encountered when using prior art molds comprising various types of fluted or corrugated primary sides. As to the mold disclosed by way of example, the relative dispositions, curvatures, and .extents of the primary mold wall portions and primary ingot surface portions are now preferred. It will be understood, however, that some changes may be made in the contours disclosed herein without departing from the invention as defined in the claims.

I claim:

1. An ingot moldhaving two oppositely disposed primary side wall portions each of which comprises longitudinally extending outwardly projecting marginal wall portions, a longitudinally extending atively abruptly curved concave wall portion mold, is defined by an arc having its center substantially on the mold transverse center'line normal to said primary side wall portion, two relatively smoothlyLcurved convex wall portions respectively connected to said marginalwall portions and extending toward said central wall portion, and two relatively abruptly curved convex wall portions respectively interposed between and connecting the opposite longitudinal edges of said central wall portion with said relatively smoothly curved convex wall portions, said relatively him, at any cross section or the their respective centers on opposite sides of said transverse center line, the radii of the arcs definingsaid relatively abruptly curved convex wall" relatively smoothly curved convex wall portions respectively connected to said marginal wall portions and extending toward said central-wall portion, and two relatively abruptly curved convex connecting the opposite longitudinal edges of said central wall portion with said relatively smoothly curved convex wall portions, said relatively smoothly curved convex 'wall portions, at any cross section of the mold, being defined by arcs having substantially a common center lying substantially on said transverse center line, and

said relatively abruptly curved convex wall portions at any cross section being defined by arcs having their respective centers on opposite sides of said transverse center line, the radii of the arcs defining saidrelatively abruptlycurved convex wall portions being substantially twice as long as the radius of the arc defining said concave wall portion.

3. An ingot mold having two oppositely disposed primary side wall portions eachof which comprises longitudinally extending outwardlyprojecting marginal wall portions, a longitudinally extending relatively abruptly curved conwall portions respectively interposed between and connecting the opposite longitudinal edges of said 'central wall portion with said relatively smoothly curved convex wall portions, said relatively smoothly curved convex wall portions, at any cross section of the mold, being defined by arcs having substantially a common center lying substantially on said transverse center line, and said relatively abruptly curved convex wall portions at any cross section being defined by arcs having their, respective centers on opposite sides of said transverse center line, the radii of the arcs defining said relatively abruptly curved convex wall portions being materially longer than the radius of the arc defining said concave wallportion, and the radii of the arcs defining said rela-' ing at least four times longer than .the radius of the arc defining said concave wall portion. EMIL GA'IHMANN.

wall portions respectively interposed between and cave wall portion which, at any cross section of tively. smoothly curved convex wall portions be- 

